Methods and apparatus for the treatment and purification of wastewaters such as domestic sewage using a biological filter has been taught in my previous patents, namely U.S. Pat. No. 4,997,568, issued Mar. 5, 1991 for a Process and Apparatus for a Biological Reactor to Purify Water, U.S. Pat. No. 5,281,332 issued Jan. 25, 1994 for a System for Treating Sewage or Other Fluids, and U.S. Pat. No. 5,632,896, issued May 27, 1997, for a Method for Treating Sewage and Other Liquids; the disclosures of each one of the just mentioned U.S. patents is incorporated herein in their entirety by this reference. Since the time of development of such devices, however, sewage and waste water disposal requirements have continued to become stricter. And, the need for compact, highly efficient treatment systems at remote or difficult sites has grown, especially as second homes are built at remote locations or difficult site specific issues, such as steep slopes or poor draining soils. Thus, the provision of systems for small scale, on-site sewage treatment has become increasingly important at remote locations which are not served by sewers. This is especially true at locations which are on or adjacent to sensitive areas, or which are located where the native soils are not conducive to installation of traditional drain fields for sewage treatment. Also, in order for traditional on-site septic systems to work well, certain minimum soil and ground water conditions are necessary, and rather large lot sizes are often required. Locations meeting such requirements are becoming less and less available, and even when they are available, they are more and more expensive. Thus, there has been an increasing demand for high performance on-site sewage treatment systems, including for designs such as those which are taught in my prior art patents that were just noted above.
However, during the course of installation and maintenance of my prior art sewage treatment systems, I have noted an increasing and as yet still unmet need for a still more compact high performance on-site sewage treatment system. I have also noted a need for a system which eliminates the need to dig a hole into the native soil in order to install the apparatus. And, in some situations, it would be advantageous for an on on-site wastewater treatment unit to be suitable for relocation to another spot on the same property, or to another piece of land at another location. Moreover, many of the compact aerobic residential on-site sewage treatment systems sold by others have unacceptably low performance, even when relatively new, as shown by various studies such as described by the article entitled “Aerobic Residential Onsite Sewage Systems: An Evaluation of Treated-Effluent Quality,” by M. Maxfield, et al, in Journal of Environmental Health, October 2003, pp. 14–19. In that study, in which samples from 184 residences with on-site sewage treatment systems were tested (and in which seventy seven percent (77%) of the units were less than one year old), it was shown that over a third of the three common brand name units installed, namely Multi-Flo™, NorweCo™, and Whitewater™ brand systems, failed to meet the National Sanitary Foundation (NSF) certification standards for biological oxygen demand (BOD5) and total suspended solids (TSS) in the treated effluent. And, over two-thirds of the systems failed to meet the Washington State Board of Health Treatment Standard 2 for BOD5 and TSS. Furthermore, an average of 59% of the systems failed to meet Washington State standards for fecal coliform in the treated effluent. Consequently, there still remains an as yet unmet need for a compact, high performance on-site wastewater treatment apparatus which produces nearly undetectable levels of the common sewage contamination parameters including odor, fecal coliform bacteria, biological oxygen demand, and total suspended solids, and which produces a purified water product that can be disposed of without concern for human contact or environmental pollution.
The foregoing figures, being merely exemplary, contain various elements that may be present or omitted from actual implementations and process configurations of the wastewater treatment apparatus and process system taught herein, depending upon the circumstances. An attempt has been made to draw the figures in a way that illustrates at least those elements that are significant for an understanding of the various embodiments and aspects of the invention. However, various other elements of unique wastewater treatment apparatus are also shown and briefly described to enable the reader to understand how various features, including optional or alternate features, may be utilized in order to provide an highly efficient, high effluent water quality in a compact, on-site, surface mounted wastewater treatment system that can be provided in a desired size and configuration for providing a long lasting and efficiently performing on-site wastewater treatment units.